A class of adhesive compositions known as thermoplastic or hot melt adhesives have enjoyed continually increasing usage in many industrial applications. These adhesives, or hot melts, as they are commonly designated, are solid or semisolid combinations of film forming resins, tackifying resins, rubbery polymers, plasticizers, waxes and similar materials which are added to the adhesive composition in order to impart various properties thereto.
Adhesive bonds derived from hot melts are particularly useful because (1) they are 100 percent solid materials and (2) they quickly form tough adhesive bonds simply by cooling--i.e. no need for solvent evaporation, etc.
Adhesive derived from hot melts are particularly useful because of their very rapid set up or bonding time. Strong bonds are formed when the adhesive cools below its melt point and crystallizes. There is no long wait for solvent or water evaporation or for chemical curing as with other type adhesives. chemical curing as with other type adhesives. Depending on composition, hot melt adhesives can be prepared having good tack, high bond strength, good flexibility, low temperature properties, good environmental resistance etc.
A typical class of hot melt adhesive composition utilizes polyolefin polymers as the base or carrier material. The polyolefin base is usually blended with other polymers and copolymers, resin tackifiers and with modifiers and additives.